The stone forests

Dec 20, 2007 15:23 GMT  ·  By

1.A rain forest represents an explosion of life, the peak of biological diversity on Earth.

But the trees that make the current rainforest emerged during the Cretaceous, at the sunset of the dinosaur realm. So, when did the first rainforest appear? And how did it look like?

The underground workings of a coalmine, in Illinois, US, revealed the world's oldest rain forest: it is 300 million years old, from the Carboniferous period, when world's best coal's resources formed.

The plants that made it are all gone now: club mosses (a type of fern), over 40 m (133 ft) tall, covering a sub-canopy of tree ferns and tree-sized horsetails (another type of fern); their living relatives are just tiny herbs. Earth's first rainforests were highly diverse in tree species and changed across the ancient landscape.

A major earthquake 300 million years ago sank the whole area under sea level and the marine sediments that covered the forest fossilized it.

This is also the largest fossil forest ever discovered: it has over 10,000 hectares, 10 x 10 km (6x 6 mi).

2.But the world's oldest forests, during the Devonian era, 385 million years ago, were made of slender trees about three stories tall and with a top made of branches lacking leaves that resembled bottlebrushes.

In 2007, in New York State, mineralized stumps of 385-million-year-old trees have been found. They were fernlike cladoxylopsids.

3.In 2007, fossilized trees, 8 million years old, dating back from the time when Europe was a subtropical wet paradise, were discovered near the village of Bukkabrany, in northeastern Hungary. Miners uncovered the strange find while carving for lignite. So far, there have been uncovered the remains of 16 trees, varying in size from about 13 to 20 ft (4 to 6 m) tall and 5 to 10 ft (1.5 to 3 m). Researchers are amazed by the fact that the trees did not petrify (turned to stone), as fossilized trees usually do.

The trunks kept their original wood, offering to the researchers crucial clues about the geology and climate of ancient central Europe. 8 million years ago, the Pannonian Lake, covering much of present-day Hungary and its neighbors, had started to shrink. At the same time, global sea levels had started to drop, fact that made all or part of the Mediterranean Sea dry up.

Today, swarm cypresses (Taxodium species) are restricted only to the warm swamps of the southeastern US and eastern Mexico. In Europe, they disappeared during the Ice Age, as they did not find a warm and wet refuge.

4.The Stone Forest of Shilin-Lunan (Yunnan) is located in the Lunan Yu Autonomous County, 126 km (79 mi) southeast of Kunming, at altitudes of 1,700-2,000 m. It has an area of over 340 square km (210 square mi) and it is a typical karst formation, carved in a vast stretch of limestone sediment formed on a seafloor 270 million years ago. About 200 million years ago, various fantastic stone forms emerged, like peaks, pillars, corridors, towers, pyramids and stalagmites, like a vast forest of stone. The stones in the rock labyrinth got various local names: "Phoenix bird adjusting its feathers", "rhinoceroses watching the moon", "Ashma" (the name of a legendary hero of the local ethnic group, Yi), "monkey on the elephant back", "mother and son", "the teeth of the dragon" and others. The limestone formation is dated from Permian, 250 MA ago.

5.Petrified Forest National Park from Arizona comprises a surface of 218,533 acres (341.5 sq mi; 885 km?) of petrified wood, mostly of the species Araucarioxylon arizonicum, 170 million years old.

The wood is transformed into jasper and agate. The trunks did not grow there, but were carried by waters, which piled them, making deposits up to 50 m (160 ft) thick. Normally, the wood would have turned into coal, but in this case it was mineralized. After that, the forest was covered by red and yellow sediments, which later were removed by wind and water.

6.The largest petrified forest in the world is found in Lesvos Island, Greece (the second being Arizona's Petrified Forest). The surface comprising the villages of Eressos, Antissa and Sigri is very dense in fossilized tree trunks. Isolated fossils are encountered in other parts of the island, like the villages of Molyvos, Polichnitos, Plomari and Akrasi.

7.Ginkgo Petrified Forest State Park/Wanapum Recreational Area is a 30 km? state park at Vantage, Washington containing petrified trunks of over 50 species like ginkgo, sweetgum, redwood, Douglas fir, walnut, spruce, elm, maple, horse chestnut, cottonwood, magnolia, madrone, sassafras, yew, and witch hazel, all 14 million years old. Today, Ginkgo grows naturally only in China.

Photo Gallery (2 Images)

Petrified Forest, Arizona
Stone Forest, Yunnan
Open gallery